Immobilizers for vehicles are well known. With the increasing costs associated with the theft of vehicles and their cargoes, many vehicle immobilization systems have been developed to make the theft of vehicles and cargoes more difficult. Such immobilization devices have included both mechanical and electronic means of preventing or making it more difficult to move a vehicle.
Current systems are generally designed for personal automobiles, while the subject invention is designed to meet the unique considerations associated with vehicle theft in the commercial trucking industry. Further, the trucking industry has been identified as a potential target for terrorist activities and increased security awareness is seeking higher levels of protection from unauthorized access.
Mechanical immobilization devices generally provide some form of physical impediment to the normal operation of the vehicle. For example, wheel clamps are a known form of vehicle immobilization that effectively prevents the wheels of a vehicle from being rotated. Other devices such as steering-wheel lock bars are also used by preventing the steering wheel of the vehicle from being properly operated. While such physical immobilization devices are effective in many situations, they are also disadvantaged in a number of ways. For example wheel locking clamps are cumbersome for the operator to properly install on a vehicle as they require the physical manipulation of relatively heavy components around the wheel of the vehicle. Installation of such systems is particularly disagreeable during cold or inclement weather and, as such, the design of such systems leads to their inconsistent use. Other mechanical systems such as a steering-wheel blocking devices are similarly disadvantaged by the ease with which such devices can be overcome. For example in many circumstances, the steering-wheel blocking device can be removed by inflicting relatively minor damage to the steering-wheel of the vehicle so as to enable the removable of the blocking device.
Accordingly, the use of electronic systems is preferred as such devices require relatively simply activation procedures from within the vehicle thereby promoting a more widespread use. Typically an electronic immobilization system will require a vehicle operator to insert a mechanical key, utilize a transponder device or enter a code on a key pad in order to enable a vehicle to be started by the regular ignition key of the vehicle. Other systems require a coded proximity sensor to be placed near a sensor so as to prevent deactivation of a vehicle.
While such systems are relatively effective in that they present a relatively simple procedure for use, they do not provide full protection to a vehicle in all operating conditions. For example, truck drivers will often leave their vehicle running when they stop their vehicles at road-side service centres or other unsecured locations. Vehicles may be left running to provide power to auxiliary heating or cooling systems within the vehicle that protect cargo or may be left running during periods of extreme cold weather when restarting an engine may be difficult. Basic preventative actions such as locking the vehicle doors may not be sufficient to prevent an unauthorized person from gaining access to the vehicle and thereby making off with the vehicle and its cargo.
Accordingly, there has been a need for an improved vehicle immobilization system that enables a vehicle to be effectively immobilized when it is both turned off as well as when it is running. In particular, there has been a need for a system that recognizes the departure of an authorized driver from a running vehicle and that will prevent an unauthorized driver from moving the vehicle if such a driver gains entry into the vehicle. Therefore, there is a need for a vehicle immobilization system that provides both active and passive protection to a vehicle while running.
A review of the prior art realizes that such a system has not heretobefore been proposed. Examples of such past systems are disclosed in prior art patents including U.S. Pat. No. 5,559,491, U.S. Pat. No. 5,394,135, U.S. Pat. No. 6,356,186, U.S. Pat. No. 5,828,297, U.S. Pat. No. 3,718,202, U.S. Pat. No. 5,635,901, U.S. Pat. No. 5,519,255, U.S. Pat. No. 5,315,286, U.S. Pat. No. 5,101,926, U.S. Pat. No. 4,838,377, U.S. Pat. No. 5,115,145, U.S. Pat. No. 5,745,030, U.S. Pat. No. 6,060,981 and U.S. Pat. No. 6,581,712.